Colortune spark plug.

[OleO]

  Has anyone tried the "Colortune" spark plug?
It's a spark plug, with a clear glass insulator, that allows you to
see the color of the flame in your combustion chamber.
Supposed to allow you to fine tune the mixture.
Too yellow is too rich. A rich, blue color, like a well-adjusted
oxy torch, is supposed to indicate the ideal mixture. Pale blue is
supposed to indicate a too lean mixture. I'm still perusing the 'net
for information. Some seem to swear by it, others think it's snake
oil.
 

[barenekd]

I have one that I used to use on my old English sports cars. They work extremely well. Kept those cars running great.
Never tried it on a thumper, though. And I haven't owned too many carbed bikes or cars in the last 20 years.
Bare

[ERC]

The only problem it only works at idle unless you have the bike hooked up to a dyno. It's hard to check what the carb mixture is doing at high speed in gear, unless you can run fast alongside it looking into the insulator.     ERC

[mplayle]

Had one many years ago when I was first getting started in classic Minis.  As ERC says, they are only good for setting the idle mixture and rely on a fully working electrical system.  Any shortfall/weakness in the ignition system throws them off - weak spark, ballasted ignition, worn points, etc.

For near total range monitoring/adjusting, a modern wide-band O2 sensor and Air/Fuel ration meter is the way to go.  Using that method on my latest Mini running is Mikuni HSR carb to replace the worn out Weber that was on it instead of the standard SU.

[OleO]

The only problem it only works at idle unless you have the bike hooked up to a dyno. It's hard to check what the carb mixture is doing at high speed in gear, unless you can run fast alongside it looking into the insulator.     ERC

They offer a plug wire extension and "viewing tube" to look at the plug when
in a less-than-ideal location. It appears there's a built-in mirror as well.
Shouldn't be too tough checking the plug on the Bullet. It's quite accessable
under the left side of the fuel tank.

I appreciate everyone's feedback. I've been intrigued by the concept of a
clear sparkplug since first reading about it in a motorcycle magazine
in the early 70s. There just might be a Colortune in my future.

[ERC]

The kit I bought 30yrs ago has what you mention. Basically they are for idle only. I wouldn't waste money on one.   ERC

[barenekd]

With the old SUs, I ran the speed up considerably from idle and watched the Mixture change and use that to set the needle. Like I said, the cars ran remarkably well. These were SCCA road racers. Bugeyes and TR-4s.
Bare

[Ice]

Colortune+go pro camera+Bluetooth smart phone display= visible jetting results on the go !

or depending on vibration,,,,

modern art in real time.

[boggy]

Colortune+go pro camera+Bluetooth smart phone display= visible jetting results on the go !

That's smart! Even if you just use it to film and playback.  You certainly won't burn your hand trying to unscrew a red-hot sparkplug during a plug chop.

And they say electronics are ruining motorcycling...

[Kevin Mahoney]

I had many MG's and used them. Mainly because I had them and thought they were cool. I am not sure they would work well enough to keep a single going very well.